In this undated photo provided by the California Department of Fish and Wildlife, a captured male red fox is seen. California wildlife biologists say they have caught two rare Sierra Nevada red foxes in three weeks. The red fox was listed as threatened in California in 1980. Scientists studying the animal had not been able to capture a red fox in a decade. The Sacramento Bee reports Thursday, March 8, 2018, that a nearly nine-pound female walked into a trap Tuesday near Manzanita Lake in Lassen Volcanic National Park. Scientists with the Department of Fish and Wildlife say they took blood samples and put tracking collars on the animals. (California Department of Fish and Wildlife via AP) less

In this undated photo provided by the California Department of Fish and Wildlife, a captured male red fox is seen. California wildlife biologists say they have caught two rare Sierra Nevada red foxes in three ... more

Photo: AP

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In this undated photo provided by the California Department of Fish and Wildlife, Pete Figura, left, and Deana Clifford of the California Department of Fish and Wildlife release a male red fox back into the wild. California wildlife biologists say they have caught two rare Sierra Nevada red foxes in three weeks. A nearly nine-pound female walked into a trap Tuesday, March 6, 2018, near Manzanita Lake in Lassen Volcanic National Park. A 10-pound male was captured February 13 just outside the park. Scientists with the Department of Fish and Wildlife say they took blood samples and put tracking collars on the animals. less

In this undated photo provided by the California Department of Fish and Wildlife, Pete Figura, left, and Deana Clifford of the California Department of Fish and Wildlife release a male red fox back into the ... more

Photo: Corrie McFarland, AP

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California scientists catch 2 elusive Sierra Nevada red fox

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SACRAMENTO, Calif. (AP) — California wildlife biologists have caught two rare Sierra Nevada red foxes in three weeks, a feat they say it's a "huge" step to understanding the animal listed as threatened in the state in 1980.

A nearly 9-pound (4-kilogram) female walked into a trap this week near Manzanita Lake in Lassen Volcanic National Park. A 10-pound (4-kilogram) male was captured Feb. 13 just outside the park, the Sacramento Bee reported Thursday.

Scientists in 2018 intensified their study of the animal but had not been able to capture a red fox until now.

"This is huge," said Jennifer Carlson, an environmental scientist with the California Department of Fish and Wildlife.

Biologists took blood samples and put tracking collars on the animals before returning them to the wild.

Electronic tracking will allow biologists to know more about the size of the elusive red fox's home range and hopefully learn more about den sites and reproductive rates.

"We know so little about this animal, and we have never found a den — ever," Carlson said.

Carlson estimated there are around 20 individuals in the Lassen group, likely too few to sustain a population under ideal conditions.

The Sierra Nevada red fox once roamed widely in the upper mountain sub-alpine zones of California's Sierra Nevada and Cascade ranges, but its abundance and distribution has declined dramatically in the last century. In addition to the Lassen population, a group exists at Mt. Bachelor in central Oregon, experts say.

The Sierra Nevada red fox requires a specific high-elevation habitat that has been shrinking. Another threat to its future is in-breeding, Carlson said.

Scientists are collecting fox scat and hair samples to build a database that will help them understand the animals' genetics and how the individual Lassen foxes are related.